Read it over and over to check for interpretation errors.

It never hurts to read over your conclusions more than once. Anyone can make typographical errors and those errors can run from ones that are irritating in a minor way (spelling “Castile” when you mean “Castle”) to ones that restate facts (mixing up a father, son, cousins or worse yet an older gentleman as senior and a non relative younger man as junior, thinking they are father son combo). Even if the typographical errors have been removed and the facts are straight, have someone else look at your writing. They may catch errors you don’t–particularly conclusions that may not be clear or phrases that don’t convey quite the message you think they do.